Tuesday, June 17, 2008

Measuring Power - II

As the previous post indicates, I am now measuring the kWh used to charge the car. I've been keeping track of per-day costs, and here is the chart for the first couple of weeks. As you can see, the cost per mile does not correlate well with the miles driven - which means that the theory I had about the rebalancing contributing a major portion of the cost for short trips seems to be incorrect (at least, for the length of trip that I've been taking).

The gap in the chart is for when I watered the batteries - no miles on that charge, so no wH / mi.

Over this period, I have driven 111.4 miles, and used 54.9 kWh to recharge. This nets out to an average of 493 Wh / mi (as shown by the green line on the chart). My electricity costs 7.5 cents per kWh, which means my average cost per mile is 3.7 cents, which, at $4.00 per gallon, is the equivalent of 108 MPG.

4 comments:

Quite impressive! I have found your blog through youtube, and I want you to know that I included your blog and video on my http://eco-friendly-lifestyle.co.uk blog. I find your explanations very informative and helpful, especially for laypeople like me. Keep up the good work!

Thanks - I'm glad you found it useful. For what it's worth, I started out as a layperson and educated and trained myself along the way. As long as you are patient and keep track of all the details, you do not need to be an expert to do this.

About Me

I was a PSD Board of Education member from 1999 to 2007, and spent nearly 3 years as its president, from 2003-2005. I currently represent Fort Collins' District 5 as its Councilmember. In my private life, I'm a lead engineer with nvidia, a computer chip design company. I have converted two cars from gasoline to electric. Past hobby computer projects include Hoverball and Adventure Definition Language.